Production of a highly concentrated probiotic culture of Lactococcus lactis CECT 539 containing high amounts of nisin.

In this study, probiotic biomass and nisin productions by Lactococcus lactis CECT 539 were followed in two realkalized fed-batch cultures in diluted whey (DW) supplemented with KH2PO4 up to a total phosphorus concentration of 0.459 g/L. Increased biomass (5.12 g/L, 2.18 × 1010 CFU/mL) and nisin (235.23 BU/mL) concentrations were obtained in the culture fed concentrated whey and concentrated mussel processing waste (CMPW) medium supplemented with glucose up to a concentration of 400 g/L (CMPW + G medium) compared with similar fed-batch fermentations in DW medium. In the second fed-batch fermentation, the feeding medium CMPW + G was supplemented with KH2PO4 up to a TP concentration of 3.21 g/L. With this approach, increased production of biomass (5.49 g/L, 2.33 × 1010 CFU/mL) and nisin (257.59 BU/mL) was obtained. Considering the substantial availability of these wastes at very low prices from local dairy and mussel processing plants in Galicia, their use as culture media could offer an attractive alternative for a low-cost production of probiotic biomass and nisin at a high scale.